This seems very sloppy.

This service typically uses various keywords to find out whether people have positive, negative or neutral reactions to different brands and products.

How do you control for negative feelings people have to their own bad teams? (Hence Indians showing up on the list )

I would hypothesize a lot of Indians, Orioles, and Nats fans have negative reactions to things associated with their own teams, while negative reactions to the Yankees and Red Sox are due to being hated by other teams’ fans.